This is NOT found in the faq and you don't need to beat the game to unlock it.
if you teleport straight to kings port and travel straight south you will arrive a dungeon on an island. The enemies are pretty tough with all having 2500-5000 hp. Once you kill all them and make your way to the third floor a boss battle awaits you.
4 enemies all having from 20,000-50,000 hp and deal like 300 damage a hit. I died on the second or third turn when i randomly found these guys. Anybody else find them?
Alright i beat them. i did it at level 50 with a party of:
Cthu, Umi, Sharpe, October.
-DO NOT USE OCTOBER liek i did, worst decision I made. Bring Ember. October died every single turn because of her low hp.
-Bringing DEM along with the sole purpose of spamming potions would also be a better idea than using UMI. His defense and HP stats are super high.
Work on one enemy at a time from least hp to most hp. The archer is the most dangerous in the fight with the highest dps. Don't worry about combos.
Winning gets you a ton of exp and +50 to all stats. Now nothing can touch you.